drrionelli: Here's a thought...
If we consider that ANYBODY with an "advantage" in ANY particular endeavour is more likely to exploit that advantage, let's consider the possibility that the black men with the more prodigious endowments are the ones who will likely use those assets to their advantage, much as a tall man will use his height to advantage in a game of basketball, or that ANY man will use his large penis for sexual gratification on a mental level (because, face it, even the smallest ones work the same way). From an evolutionary standpoint, yes, the large penis is, to the mate, a sign that this person is more likely than not capable of providing gratification via the production of offspring, much as a powerful musculature suggests the ability to procure food and defend against enemies.
So, could it not be that black men are, indeed, no bigger (and no smaller) than their non-black counterparts, but that the anecdotal findings suggest otherwise? And, as we all know, anecdotal evidence is flawed by its own nature. Thus, if ,and only if, a large scale (no pun intended) study is done to collect and analyze empirical evidence--a daunting task to say the least--then to even conject as to any putative size difference makes the point moot.